Ultrasensitive electrochemical immunosensor for procalcitonin with signal enhancement based on zinc nanoparticles functionalized ordered mesoporous carbon-silica nanocomposites

A novel and sensitive strategy for procalcitonin (PCT) determination was developed based on zinc nanoparticles-functionalized ordered mesoporous carbon-silica nano-composites (OMCSi-Zn). This strategy combined an effectively designed trace tag and a simple immunosensor. The large amount of OMCSi-Zn materials as label greatly amplified the detection signals for the electrochemical detection of proteins, while the good biocompatibility of graphene-chitosan as sensor matrix retained excellent stability and accelerated electron transfer for the sandwich-type immunoassay. Without metal preconcentration, the zinc nanoparticles loading on the ordered mesoporous carbon-silica nano-composites (OMCSi) could directly be detected through electrochemical voltammetries, while the immunoreaction had a close relationship with the distinct voltammetric peaks. The proposed method exhibited high sensitivity and good stability for PCT detection, possessing an improved linear response range from 0.05 pg/mL to 80 ng/mL, with a detection limit of 0.013 pg/mL (S/N = 3). Moreover, the serum samples from clinic were accurately detected with the proposed method, indicating that the developed immunoassay possessed excellent potential application in clinical diagnostics for PCT. (C) 2017 Elsevier B.V. All rights reserved.